Electrical apparatus



Jan- 8, 1952 c. lA. P. ,JoHNsoN ET A1 j 2,581,861

ELECTRICAL APPARATUS Filed Feb. ,9, 1950 Patented Jan. 8, 1952 Carl-A A. P.' Johnson; North QuincmeandllArchieg'l'. s Morrison, .i South Braintree, Mass.,l;,assignors,to ,Y

Masslga" corporation of Massachusetts Y Applicationflebruary, 1950, SerialfNo.=:143,252:; 2 Cimq (Cl. 20o-511)' Theipresent Ainvention relates lto aco-operating; electric plug and receptaclewhich may be-fused 1n;

aV xedposition .or on a portable line or cable and is-particularly designedv forense in connection with special annunciator` systems v as,,for instance, the. kind generally used in hospitals for bed patients incalling for aid and signalingthe attentionof'` attendants or nurses. Y

In mostv ofv suchrhospital Ysystems Athe-patient .in thefgbed has an electriclcord near the, bedzwhichends in a push Ybutton.` The cord is usually pluggediinto a wallireceptacle which has electricalconnections to `a: number of places. When the patient wishes to call or signal, he presses the push button and-visualand audible signals are produced at variousplaces as, .for instance, in the nurses oice; in'frontofthepatients door (where a light usually appears), and in several other places.

In order to be assured that A.the patient may at alltimes signal for aid, specialimeans have 4.been employedto make certain thatthe circuit always remains inworking order so that when thepatient presses thebutton, thepropersignals will beproduced. One common di'iiiculty experienced in the past has been that the cords and plugs come out or are pulled out of their receptacles with the result that when the patient signals, the cord is dead and no electrical connections are made. Various methods and devices have been employed in the past for producing a signal merely when the plug comes out of the receptacles, which is the general subject matter of the present invention, so that 'the attendants know when the plug has been disconnected.

The present invention has advantages over the devices in the prior art inasmuch as no rotating elements are used and the device is simply constructed and of a fool-proof nature.

'I'he present invention is a division of our copending application, Serial No. 597,472, led June 4, 1945, Patent No. 2,500,184, in which the present form of invention was shown. The difference between the present modication and that de scribed and claimed in the original case is that the action is positive in the operation of the switch effected entirely by the insertion or the removal of the plug in the receptacle. The removal of the plug acts in a positive manner to pull out the connecting jack element so that the circuit will be completed.

The invention will be more fully understood from the specification annexed hereto when taken on connection with the drawing in which the figure shows a broken section through the receptacle and part of the plug.

In-the arrangement indicatedin .the gure, the,

individual receptors and theconnector terminals: are substantially the. saine;y asin lthe modification,l of Eigure 2- of our col-pendingcasewhichhas.,

matured into saidpatent. .In the present case,

however, the'spring lingers-32,r 32- are/turnedfin the; reverse direction outwardly in the .f direction of theV front face of. thereceptacle.` The-jack 33 has a'ninsulating body` portion 34 :.towhich a. conductive member-361s attached.VV Thismember35 is `provided withV .al cylindrical vvconducting portion-= of-zthe; insulatinggpart of thegj ack. At ioneVr end A ofk the-,conducting member r35;:there; extends an: axially located= pin` elementi 38 -andrat the :otherY end Vof the electrical conductive. member-.,35gthereV Thepin 38 fltsVf-reely lfor vlongitudinal `motion in,

a-hole 39 inthe wal140 at theendofitherecepf with allonginsulating neck .'portion Miajoinedf to the,E central` insulating cylinder 31a" inea smallf, shoulderf42. The-neckportion-4l ofqtherjackhas,

a sliding t in the hole 42' in the front plate of the receptacle. This hole is just large enough to permit free motion of the neck portion 4I until the shoulder 42 comes to rest on the inside surface 43 of the insulating plate member 44' when the plug is moved to the right from the position as shown in the figure.

The front end of the jack 33 is provided with a rounded head member 44 which has an arcuately shaped or gouged out neck portion 45 in which the curved doubled prong spring having prongs 46 t. This spring is riveted to the plug member 41 at the end wall of the cavity 48 in the face of the plug member. A pin 49, postioned centrally between the prongs 46 in the cavity 48, is aligned to engage a centrally located recess in the end of the rounded head 44. The spring prongs 46 and its support has a section of a general reversed C shape. 'Ihe pin 49 will ensure the plug being pulled out axially with the jack 33. 'Ihe spring prongs 46 are made sufllciently strong so that the jack 33 is firmly gripped when the plug is put in place. If the plug is accidently removed or removed on purpose, the grip of the spring ngers 46 on the jack 33 will make certain that the jack is pulled outward with the receptacle until the shoulder 42 comes up against the face 43 of the insulating wall 44. When this occurs, a circuit will be completed through the conducting cylinder 36 and the annunciator circuit will function in the usual manner.

The spring iingers 32 should have sufficient pressure on the jack member so that it will remain in whatever position it isplaced. For this purpose bothvtheins/ulating section 31 and the conductive section 35 may be provided with cir` cular grooves 50 and 5| respectively on the face4 of the jack to aid in retaining the jack in one of its two positions. In this way if the lplug is removed, the jack will remain in its outward position until restored manually by pressing-the andV receptacle assembly :comprising areceptacle casing having a plurality of elecend of the head 44. If the plug is returned to its position in the socket, the jack will be Vpushed inward, breaking the circuit and at the same time the spring fingers 46 will come to rest inv the arcuate sides of the collar portion of theA head.

The invention has been described in connection with a receptacle and plug showing five circuits. It is obvious that not all of these need be used and that the plug and receptacle may be used or designed with one or more receptors and connectors although, because of symmetry, the use of a plurality of receptacles is preferable.

Having now described our invention, we claim:

l. A plug andvreceptacle assembly comprising a receptacle casing having a plurality of electrical receptor members positioned about a central longitudinal axis of the receptac1e, a'plurality of spring arms also positioned about and extending longitudinally with said longitudinal axis of said receptacle, said spring arms being electrically connected to lsaid electricall receptors, a connecting jack having a flanged end with a concave groove behind the end extending all around the jack and having insulating sections and conductive sections along portions of its surface and having longitudinal axis parallel to the central axis of said receptacle, means supporting said jack in said position for reciprocal motion conned to its longitudinal axis, a plug member havingv spring prongs with inwardlyrconcave ends adapted to engage in the trical receptor members positioned about a central longitudinal axis of the receptacle, a plurality of spring arms also positioned about and extending longitudinally with 'said longitudinal axis of said receptacle, said spring arms being Aelectrically connected to said electrical receptors,

a connecting jack having insulating sections and -cond-uctive .sections along portions of its surface and having longitudinal axis parallel to the central axis of said. receptacle, means supporting said jack in said position for reciprocal motion, aplug member having means adapted to engage said jack when the plug pins'are'inserted in the receptacle, said means ,comprising' a recessed neck portion adjacent the forward end of the jack and spring gripping meansl mounted in said plug and adopted to come into said recessed neck portion when the plug has been attached, connecting said plug and jack v together whereby when said plug is removedfthe jack will be moved outward to a circuit closing file of this patent: y

UNITED STATES PATENTS l v Date Y' Number "l Name Y 1,711,397 Rumble Y. Apr; 30, 1929i 1,911,513A v Kenerson May 30, 1933' 2,032,038. Auth Feb. 25, 1936 Johnson et al. Mar. 14, 1950 

